#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>

using namespace std;

int main() {
	int t, n;

	cin >> t >> n;
	vector<int> c(n, 0); // time
	vector<int> v(n, 0); // satisfaction
	for (int i = 0; i < n; i++) {
		cin >> c[i];
	}
	for (int i = 0; i < n; i++) {
		cin >> v[i];
	}

	vector<int> memo(t + 1, -1);
	memo[0] = 0;
	for (int i = 0; i < n; i++) {
		for (int j = t - 1; j >= 0; j--) {
			if (memo[j] != -1) {
				int point = v[i];
				int add = 0;
				for (int k = 1; point > 0; k++, point /= 2) {
					int now = j + k * c[i];
					if (now <= t) {
						add += point;
						if (memo[now] < memo[j] + add) {
							memo[now] = memo[j] + add;
						} else {
							break;
						}
					}
				}
			}
		}
	}

	int ans = 0;
	for (int i = t; i >= 0; i--) {
		ans = max(memo[i], ans);
	}

	cout << ans << endl;
	return 0;
}